A quarter of a million civil servants are to join striking teachers for a mass walkout on 30 June, bringing schools, colleges, universities, courts, ports and job centres to a halt.

Up to 750,000 state employees are expected to take part in the strike, over the government's pension reforms, after members of the Public and Commercial Services union voted by 61.1% in favour of strikes, and by 83.6% for other forms of industrial action, on a turnout of 32.4%.

Mark Serwotka, the general secretary of the PCS, said the action was principally against cuts but also against the coalition's public service reforms.

"The clear majority in favour of a strike shows that public servants – who provide vital services across the country – are not prepared to stand back while everything they have ever worked for is taken from them," he said.

"The government claims this is about rebalancing pensions, but it has already admitted that the money it saves will go straight to the Treasury to help pay off the deficit in what amounts to nothing more than a tax on working in the public sector.

"I have been at every one of the negotiating meetings with the government, and what we've been told is that they won't budge on increasing the pension age, they won't budge on their plans to double or triple contributions, and they won't budge on the value of our members' pensions being slashed.

"In reality, the talks are a farce and, faced with mass job cuts, the pay freeze and the biggest raid on pensions in living memory, it's not surprising that people want to defend themselves."

Francis Maude, the Cabinet Office minister, has repeatedly called on the unions to await the outcome of the pensions talks that are currently under way before striking, calling those going ahead with industrial action "irresponsible and wrong".

He said: "What today's ballot result shows is that, among PCS members, there is extremely limited support for the kind of strike action their leaders want.

"There was a very low turnout for this ballot, and less than 20% of their members are supporting this unnecessary industrial action.

"This is not surprising given that talks with the TUC about public sector pensions are continuing – there is no justification for any civil servant going on strikes while discussions are continuing.

"Public sector pensions will remain among the very best, providing a guaranteed pension level for all employees. Today, very few private sector employers still offer guaranteed pension levels.

"We continue to hope that industrial action will not take place, but in the unfortunate event that it does we can assure the public now that all services have highly developed and rigorous contingency plans".

David Cameron's official spokesman said the government wanted "an open and constructive dialogue" with unions.

The spokesman said ministers were keeping "under review" the question of whether laws on industrial disputes should be tightened, but did not, at present, see a "compelling case" for change.

On Wednesday, it emerged that a second headteachers' union, the Association of School and College Leaders, was also moving towards a ballot for strike action.

Three teachers' unions – the National Union of Teachers, the Association of Teachers and Lecturers and the Universities and College Union – have all said they will strike this month.

Nearly every major public sector union has now indicated that it is likely to ballot once the talks conclude this summer. Insiders say negotiations are all but at a stalemate, with ministers and unions failing to agree on even basic principles.

It means there could be rolling strike action across the public sector in the autumn, which could profoundly disrupt the work of the state.

Maude told MPs during Commons questions: "It was Lord Hutton, the previous Labour pensions secretary, who recommended these reforms to make public sector pensions schemes sustainable and affordable for the future. That's what we're determined to achieve."